A stock exchange owned by Bats Global Markets Inc. halted trading shortly after the open because of an “internal networking issue,” company spokesman Randy Williams said.

The Bats Y exchange, which accounted for 2 percent of daily U.S. stock volume in September, stopped trading at 9:44 a.m. New York time, Williams said in a phone interview. The company advised customers to route orders away from the Bats Y platform and its other venues were not affected, Williams said.

Stock exchanges owned by NYSE Euronext and Nasdaq OMX Group Inc. were routing orders away from the venue before the halt.

So-called “self help” was declared by NYSE Arca and Nasdaq shortly after the open of exchanges today, according to e-mails from the exchanges received by Bloomberg News at 9:38 a.m. in New York.

On Aug 6., Bats Z Exchange, the company largest U.S. stock exchange, was closed for almost an hour because of a malfunction, also an internal network issue, Williams said at the time.